Mr Catt is a 91 year-old who peacefully participates in political protests, including with a groups called “Smash EDO” some of whom, unlike Mr Catt, commit violent offences. Information about Smash EDO is recorded on a Domestic Extremism Database. The police retained information about Mr Catt, including his presence at protests, his address and date of birth, in Information Reports primarily relating to other individuals.

Ms T is alleged to have said a homophobic insult to her neighbour’s friend in 2010. The police issued a “Prevention of Harassment Letter” a copy of which remained in the police records, but was deleted during the course of preparing for the appeal.

The police’s power to retain data is governed by the Data Protection Act 1998 (DPA), and a mandatory Code of Practice and Guidance issued under the Police Act 1996. Data must only be handled for “police purposes”, sharing between police forces is limited, and the information must be reviewed for deletion periodically, checking that it is accurate, up to date, not excessive, that the DPA has been complied with and that the assessment of the risk presented by the individual is correct.

Both claims failed at first instance and succeeded at the Court of Appeal. Supreme Court allowed both appeals, ruling the retention of data lawful. In the case of Mr Catt the Court allowed the appeal by a majority of 4-1 (Lord Toulson dissenting), and in the case of Ms T, the appeal was allowed unanimously.

In the leading judgment, Lord Sumption stated that the systematic collection and storage of information about individuals is clearly an interference with private life under Article 8(1) ECHR, the question therefore is whether that interference can be justified under Article 8(2). The two elements under Article 8(2) are whether the retention is (i) in accordance with the law, and (ii) proportionate. The retention of data was found to be in accordance with the law, although there are discretionary elements to the scheme these are limited and subject to judicial review. The real issue in the appeals was proportionality.

In relation to Mr Catt: the court found the interference to be minor, the data, whilst personal, was not intimate or sensitive, and the primary facts were in the public domain. Importantly, the material was usable and disclosable only for police purposes, or to Mr Catt himself in response to a subject access request under the DPA.

The retention of data of this kind contributes to numerous proper policing purposes, the longer-term consequences of restricting the availability of this method of police intelligence-gathering would potentially be very serious (adversely affecting police operations directed against e.g. organised crime, terrorism, drug supplying and football hooliganism) and the labour required to remove the information relating to persons such as Mr Catt would be disproportionate. Therefore the retention of the data was proportionate and as such, justified under Article 8 (2).

Lord Toulson, dissenting, took the view that the police evidence did not explain why it was necessary to retain data for so many years about someone who was known not to have acted violently, and therefore this was not necessary or proportionate.

In relation to Ms T: the Court found that retaining data about previous harassment complaints serves a vital police purpose, particularly in domestic abuse cases, and it was not unlawful for the police to retain such information for several years as standard practice, provided that the policy was flexible enough to allow it to be deleted when it no longer serves a useful policing purpose.

Lady Hale, Lord Toulson and Lord Mance found the policy to be lawful generally. Lord Sumption and Lord Neuberger found the policy to be lawful in this case as the material was in fact kept for only two and a half years, but that the standard period of retention applied by the police (retaining a copy of such letters for 7 years in the Metropolitan Police electronic records, and for 12 years in the Crime Reporting Information System) was wholly disproportionate in trivial cases such as this. The Court therefore unanimously found that the retention of Ms T’s data was not disproportionate and was justified under Article 8(2).

The judgment can be found on the Supreme Court website here, together with a press summary available here.